Process of treating wood and plants to make cellulose.



B. LOOMIS.

PROCESS OF TREATING WOOD AND PLANTS TO MAKE OELLULOSB.

' APPLICATION FILED MAR. 22, 1912.

1 1 22,404, Patented Dec. 29, 1914.

. improved products are obtained.

UNITED- STATES PATENT oiuuon.

BURDETT LOOMIS, OF HARTFORD, CONNECTICUT, ASSIGNOR TO LOOMIS UTILIZATTON COMPANY, OF EAST ORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

PROCESS OF TREATING WOOD AND PLANTS TO' GELLULOSE.

Patented Dec. 29, 1914.

Original application filed May 23, 1911, Serial No: 629,053. Divided and this application filed March 22,

1912. Serial No. 685,648.

To all whom it may concern. I

Be it known that I, Bnnon'r'r LOQMIS, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Processes of Treating Wood and Plants to Make Cellulose, tion.

This invention relates'tothe art of treating wood and other fibrous ligneous material, plants, etc.,. containing lignin, to obtain products and produce pulp and cellulose for the manufactureof paper and other commodities.

The principal object of my invention is to provide a method for economically and rapidly reduci'ng ligneous material and plants to the conditionof pulp or cellulose ready for paper making, directly in a beating engine, and'at the same time'separate and save from the raw material the various valuable constituents in condition for economic uses in the industrial arts, whereby great .cononly is efiectedvin the process and gieafly of which the following is a specifica- One of the principal objects Of fhy invention is. to provide for the extraction from wood and plants of valuable constituents and products by means of solvent and absorbent vapors and gases, such as fatty acids derived from wood and diffused in hot water and circulated at the proper temperature in contact with the material under treatment, thereby releasing and removing from the material natural constituents, such as turpentine, oils and resinous matter, and subjecting the vapors to condensation for arresting and saving the separated constitucuts, and thereby effecting economy in the process; and for reducing the ligneous or fibrous material to the best condition for the subsequent action of alkaline substances to produce pulp or cellulose, with a saving of time and a large percentum of alkali ordinarily required; also with a saving of bleaching agent.

Another object is to produce an'improved quality of cellulose, with a comparative long, stron'g'fiber from any given kind ofligneous material, and to utilize all, socalled, waste material incident to the process, so as to reduce the cost of the cellulose to the minimum.

Other objects and purposes of my invention will appear and be understood from the following detailed description of the process in connection with drawings which illustrate forms of apparatus which may be used for carrying out theprocess. K

Different kinds of wood and plants contain a variety'of constituents, such as acids, gums, wax, turpenes, oils and resinous substances, according to the character or kind of wood or plants, which sub stances are not useful or. desirable in cellulose for making paper or other products, and are, inrfact,

detrimental thereto,-but which, if, separated from the wood and from one another, are quite valuable for use in the arts, and

which when separated, leave the fiber of' wood or plants in the cleanest and best condition for making superior pulp or cellu- .mation of a number of acids of the fatty acid series, and by raising the temperature there are formed'other fatty acids. The formation of fatty acids, among which acetic acid appears in'largest quantity, commences, according to Gillot, at 255 F. Other fatty acids are formed, such as formic acid, propionic acid, butyric acid, valeric acid, etc., at the above and higher temperatures.

Simultaneously with the formation of these acids, carbonic acid, carbonic oxid and methane are evolved from the wood, and these bodies in anascent state'inay act upon the acids so that the latter may undergo decomposition by more vigorous heating and a large number of products of decomposition may be formed. Among such products are found methyl alcohol (wood spirits),

acetone, methyl acetic ether, aldehyde and of decomposition, when diffused in hot wa- 'tioned fatty acids, gases and other products I ter, are an excellent solvent for the cellular structure, the gummy and resinous material found in wood and plants, and that, if

the mixture or solution is circulated in contact with the wood or plants to be treated the contained resinous matter, oils andturpentine will be quickly liberated and may be drawn off with circulating water. The turpentine and more volatile oil will pass off in the form of vapor and will be condensed,

and the rosin will pass ofi in a melted semi liquid condition, and will be deposited and recovered. I have also discovered that the fatty acids and other solvents may be most effectively and economically produced and diffused in water by first heating fresh water and circulating it in contact with the wood or plants to be treated at gradually increasing temperatures, ranging from 212 to approximately 300 F. The volatile solvent is readily extracted from the wood or plants and diffused in the water and the mixture is passed from the wood treating tank through a heater where the temperature is raised and is then circulated up through the wood or-plants. The circulation of the water and solvent in contact with the wood or plants and through the heater, the temperature being gradually increased, is continued till the solvent has liberated the turpentine, oil,rosin and gummy matter, and ,these valuable products have been recovered. The treatment may be continued for six to twelve hours, according to the character of the wood or plants and the temperature of the treating liquor.

' By my process the pressure usually required for making pulp or cellulose will be much reduced, the time will be reduced and a smaller per'centum of chemical reducing agent will be required to obtain the desired result; and the pulp or cellulose produced will be stronger and have better fiber than that produced by the ordinary process. The pulp or cellulose prepared by my process will also require much less bleaching powder or other agent to completely bleach it, by reason of the fact that the gums and col oring matter have been extracted.

I will now describe my process more 1n detail by reference to the accompanying drawing, which represents in sectional elevation a form of apparatus in which my process may be carried out.

In the apparatus I provide five principal parts or devices consisting of a treating and distilling tank A, an expansion and depositing chamber D, D, heating coils H located in a furnace below the bottom of tank A, a condenser E, and a pulp disintegrating tank, these parts being suitably connected by valved pipes and a circulating pump being used in the connecting pipes. The closed tank A may be constructed of boiler iron or other suitable sheet metal, and has at the top a mouthpiece a provided with a cover a, and at the bottom a removable cover plate a. At the top of the tank below the mouthpiece is secured a transverse perforated screen plate B, in the middle ,rails W for convenient removal when the bolts are withdrawn.

To the mouthpiece a is connected :1 water and vapor discharge pipe C, having a valve 0, which connects with an. expansion and depositing chamber D, D, at the top of which connects a vapor or turpentine discharge pipe-e having a valve e. The pipe 0 leads to a condenser E.

The expansion and depositing chamber D, D is preferably of greater height than the treating tank and rises above the same and is about one-half the diameter of said tank, though such exact proportions are not required. At the lower end the chamber is made with tapering walls 0?, cl, terminating with a discharge pipe having a' valve (1 for drawing otl rosin. A steam coil cl is placed in the lower end of the depositing or catch-all chamber D for melting resinous material in case it becomes cold and hardened. At about middle height of chamber D, D is'pla'ced a separating dome or hood F, which may be attached at its edges to the wall of the chamber. An outlet pipe connects with .the wall of chamber D at,

the top of the dome and is provided with a valve f. The dome F is located below the connection of the water and vapor discharge pipe C from treating tank A and provides a vapor expansion chamber or space D above it, and a rosin depositing or.

catch-all chamber or space D below it. This dome acts as adeflector and separator to cause the rosin or gummv matter to be deposited in the bottom of chamber D while the water or treating liquor flows up into the dome and'thence off to the circulating pump G. A positively acting rotary pressure pump is preferably used, though some other kind of positive pressure pump may.

be employed. A discharge pipe 7 connects with the pump and leads to the lower end of a series of heating co ls ll suitably supported in av furnace K. These coils are connected in a series by means of return bends h which extend through the wall of the furnace. Near the bottom of the furnace is provided a perforated arch 75 for distributing the gas flame and protecting the.

lower heating coil. A fire chamber is provided below the arch 70. Gas is preferably burned in the fire chamber and is supplied by a pipe M having a valve m and a burner of any suitable kind m in the fire chamber.

mass

In order to secure satisfactory heating andcirculation of liquid through the apparatus, the heater is located so that the topthereof is below the bottom of the treatingand distilling tank A. a To the top of the .L is providedwitli a check' valve Z. A check w'valve g isalso placed in the-lower end of pi p'e ga t itspqnnection with the, coil. .These xcheck valvesg'prevent back flow of, water. from the v blow-01f jlpip' $5 1 11 V1 iTo pipe; L isfconnected a n M i-s wa nandsqtuin iank T.

A water'supply pipe J-N,Qhav1n a .-valve' n,

nesting wi' 11;

connectswith-theinouthpieceo tank A, or.

may connect "at other desired partof :the, apparatus, as near-the .heatir2jcoil s.,. y

A pulp receiving and disintegratingtank .0 is connected by a blo'w ofl p peLK hav-' ing a valve Z","to the bottom of tank ,and

1 is provided in its top plate with a target 0 0.' The tank is also provided at the top against, which the pul isblo 'n-for separ rating and disintegratiiig it. '%he3pipe I! terminates, in a nozzle. 1" below the target wan purge piped having a valveo for the escape ofvapors. Across the lower end of tank 0, about one-fourth ofits height v with theta the'bottom, is secured a grid andgfilter cloth 0*, providing a compartment ()f-lbe lowfior receiving. liquor, and to the bottom I ,isfcbnnected a drain pipe-o", having a valve (apron discharg ng the l q Arte connects with the bottom of the vtank and. .1

matelyf. to ;212;1.-;F..

extends up through the grid and filter cloth where its upper end is provided witha P g b9,- and this pipe servesfor dischaPg fig'.

the pulp after having been drained Agaspipe p', having a valve 79" leads from a compression pump P, and connects with tank .0 just above the pulp discharging 11oz zle l?" 'for supplying gas under: pressure to carry-01f much of the watery vapor at'the time. the pulp is blown against thetargeto, so that I much of the blackfi liqnonflwhich would ,otherwise settle with ztheltpulp onto the filter cloth,- will be takenupjand carried off with the gas. As a result-ofthis O.pera.- ti on there is left vless liquorto wash" out oi the-cellulose and therefore, the cellulose will be ml the tank,

A compression .pump' P I:

draw gas from a .holder io'r 'l l i ai'iilrom a heater 8 through pipe Qandwill connect by pipe p-wi'ththe top ofthe feed tankU and by the bra ch pipe p having valve i h mas h m one above the nozzle 2'. The purge pipe" 0 will preferably connect "by lln operating the apparatus-for carrying water through the heating coils-and the -heatingcoilsf:

"wood chips or plants chamber .1), D.,..wher r cleaner when removdYfrom pipe R, having valve'r, with a condenser E for separating water or any othercondensable matter from the gas. The gas freedfrom condensable matter will bereturned tothe. holder or to a heater.

An elevated feed-tank for holding alkaline chemical or bleaching liquor is provided .adjacentto the treating tank A which may alsobe used as a digester. Tank U is provided with a cover u, and. an outlet pipe u having a valve uf, connecting withthe top of tank A. A pipe ;0 leading from the compression pump P, and having a valve r, may-connect with the top of the. tank a U for supplying gas under pressure to force the alkalineor bleaching liquorinto out-my process, the bottom coveriai is.,close and secured by bolts, and the tank .is'then 1 filled -with chips of wood through the mouthpiece a, the slidingscreen 6 being.

that timelopen The chips are preferablyv made bylzcutting the wood across the grain,

andjmay be about an inch thick. Thettank A is preferably filled with chips up to the" .'screenv B,-and then the slidingscreenb-an'd the top cover .a are cIo'sed.-andseeured in place. Now .the. whole system, including 5 tank A,. chamber D, D p and the coils. vi

filled "withgvvater admitte'dlb'y pipe N and; caused to" riseto the level .o fthe discharge pipe C. Gas is then admitted to the burner 'm and lighted. and the. circulating-pump a." G. is started. This causeshthe; cireulat' up through the treatingand" A in contact with ,t he we circulating, wate assf w'ith .the water, As the temperatureyof the water is; gradually raised. other fatty acids, ,gases. and products of. decomposition are Pmduced are formed and? diffuses throu 9th the ater.

The hot circulating 1 Waite! andisojlve nt' fatty acids soon= commence toyd ssolv'e the cellular structure' 'and; release- 'thelturpentine,

ter the 3 ar entine and v.ter or. 'liquor into the volatile va ors separate and fill the vapor space D from volatile oil and;

oil .vaoor pass with ,th

which they passofiKthrough pipe'e to'the condenser E, where1 condensation is effected.

c othe" circulatin water confich hasz been reeased from lant matnalispassed down tier, the separating jdoi'ne \FtWhere 1 such 1 resin omgum is separated and caused to settle into the' depositing chamber-D", where it collects, -.w'hilecthe water passes-31p through the, separatorfdome F and thence by pipe, f, the irciilating pump'G, and pipe 9 into'the me fi'thelfattyacids bottom'of the heating coils. By circulating the hot Water up through the chips or plant material in tank A, the rosin or gummy mat- .ter is carried upward and floated off with the water through pipe (J into chamber D, D, Where it is deposited.

The circulating hot water or solvent liquor in tank A agitates the body of chips and prevents packing, and continuously carries "away the extracted material so as to continuously bring fresh liquor into contact with the chips to efi'ectively'exert its solvent action on'the cellular structure thereof and.

release the gummy and resinous constitu-- ents. In the expansion and depositing chamber D, D, the turpentine and oil vapor readily separate from the liquor, and at the same'time the liquor is partially cooled so that the rosin or gum is hardened and will readily settle in the bottom of chamber D. [The velocity of the flow of liquor is much retarded in the-expansion and depositing chamber, thereby facilitating the deposit of rosin. vThis action is also aided by the small overflow outlet pipe I from the top of the separating dome F.

The temperature of the Water or liquor may be gradually raised in the heating. coils to approximately 300 F. As the operation progresses, the Wateror liquor becomes charged with'an increasing percentage'of fatty, acids, gases,etc., and these act with increasing energy to dissolve, release, and

. extract the turpentine, oil -am l rosin from the vwood chips till they are substantially free from such constituents. The operationi' may be continued for a period varying from six to twelve hours, according to the char;

acter of wood being treated.

At suitable intervals, thefl'valve (1' may be opened and the rosin discharged from the chamber'D', but this may be mostly charged at'ithe end of the operation.

When the treatment and d stillation of the Wood in tank A is completed, the valve 0 may beelosed andthe blow-off. valve .9 opened, permittingthe water or liquor containing the fatty acid to be blown oif into the storage and settling tank T, Where" it'is reserved for treating a succeedingcharge of wood chips in tank A. The Wood chips or other fibrous materialin the treating-tank will now be practically free from gum;'resin, and oilv matter andlthe pores Wi'll:be open so as to be readilvipermeatedbv causticsqda solution o'rother alkaline'solution.

The cleaned chips or other -'fibrous material may be conveniently reducedfto cellulose directly in tank-A, which wbecomes a digester, by admitting-fresh Water through pipe N and the desired percent ofcaustic soda solution, or sulfite ofsoda vfrom tank U. The circulating pump .G will be put into operation and the liquor caused to cirineaeoa culatc in the direction ofthe arrows through the heater H digestion and reduction to pulp or cellulose is .completed. 7 The temperature may be raised to 250 l51, or higher if required, and at intervals more alkaline solution admitted from tank U. Gas under pressure may be admitted by pipe ;0 into the top' of tank U for forcing the alkaline solution into tank Owing tothe preliminary thorough preparation of the chips, the percentage of caustic soda, sulfite of soda or other chemical used for digesting the Wood or other fibrous material, Will be very much smaller than that required in the ordinary process. The heat and pressure will be much lower and the time Will'be much reduced for re ducing the material to a good strong fiber pulp or cellulose. Y

-The cellulo'se having been produced, gas under pressure is supplied from pump to the top of the digester, and then valve l is opened 7 and "the cellulose is discharged through pipe L and its nozzle Z against the target 0 in the top of tank 0. Here the partioleswhich' adhere together will be disintegrated and separated. At the same time gas under pressure will be-admitted through pipe p, just above the'discharge nozzle l, so as to-catch the spray-of liquor, containing coloring matter and some residue-of gummy-matter, and carry it out through the purge pipe 0". The top valve '0 may be open, soas' to blow the gas'and vapors into the open air, but the valve '0 will preferably. be'closed and the gas and vapors conducted by pipe R, 130- 11 condenser E,,*izi-'here the liquor vapor will beTcondensed, while the gas will befreed and returned to, the holder, or to aheater to be again heated and then" compressed to be use a liquor vapor. Any liquor which drains from the pulp through the filter cloth 0 will be drawn oil I-from compartment 0" as required. The pulp or cellulose may be discharged from'tank- O bV- opening valve 0 in pipe "0 into a. bleaching tank.

.The'cellulose prepared asabove described, freed from gums, resins'and' much of-the coloring matter-will be bleached to the desired extent witha comparatively small per cent. of chlorid of lime or other bleaching agent and thus great economy efi'ected, while the cellulose will have greatly increased strength otfiber. The low heat and pressure employedin the digester also contribute to the strength otthefiber in the cellulose. Owing to the reduced amount of caustic soda and the shorter time. required in digesting thefipreparedchips the fiber of the cellulose will have greater strength than and up through the chips till its valve r'being open,

by digestion with alkali or alkaline salt, to pulp or cellulose, has been completed, that is cooked in the digester A, I may draw off the alkaline liquor "through pipe 14, and admit fresh warm or cold'water through pipe dissolved or saponified oily or resinous matter. The-first wash liquor may be drawn ofl' and fresh water again admitted and circulated till the cellulose is sufficiently clean.

Strength, toughness and elasticity. are characteristic of the fiber in the cellulose produced by my process.

This application is a division-of my copendin application, Serial Number 629,053 filed 1V av 23, 1911.

Having described my invention, what I claim, and desire to secure by Letters Patent is 1 The nrocess of making cellulose, which consists in subiecting woody or vegetable fibrous material in a closed chamber to the action of hot water, circulating the water 1n contact with the material, first at a lower temperature and then at graduallv increasing temperatures, separating and collecting the extracted constituents at different stages and temperatures till the material is sufficiently freed from yolatile and soluble constituents. drawing off the treating water then adding fresh water and the necessary per cent. of alkaline chemicals and circulating the mixture through the material to dis gest the same and reduce it to cellulose.

2. The process of treating woody or vegetable fibrous material to make cellulose, which consists in subjecting it in a closed chamber to the action ofwarm or hot water, circulating the water repeatedly in contact with the material and through a heater, thereby agitating and macerating the material till the natural constitutents are extracted, then drawing off the water and extract, separating the extracted constituents in a depositing chamber during the circulating operation adding to the cleanedc mater ial fresh water and an alkaline chemical and circulating the same through and in contact with the material till reduced to cellulose.

8. The process of treating woody or vegall water and extract, then adding fresh water and alkaline chemical, and "circulating the mixture through the dlgester and a heater till the material is reduced to cellulose.

4. The process ofmaking cellulose, which consists in first extracting from Woody or vegetable fibrous material, the contained oily, resinous or gummy constituents by treating it with warm water, separating such constitutents thereby cleaning the material. then digesting with an alkaline chemical, then'forcing the resulting cellulose by gas under pressure into a receiving tank and discharging it against a target for disintegrating and separating the fiber and at the same time forcing gas under pressure into the disintegrated cellulose and discharging the resulting vapor from the tank and collecting the cellulose'in the tank.

5. The process of treating woody or vegetable fibrous material to make cellulose, which consists in subjecting it in a closed chamber to the action of warm or hot water, circulating the water repeatedly up through the material for dissolving and extracting soluble constituents, floating oil such constituents with the water and separating them in a deposit chamber drawing off the water and extract, then adding water containing a small per cent. of alkaline chemical and circulating the same in contact with the material for extracting other constituents, and drawing off the resulting watery extract, and thus repeating the operation till the material is cleaned and ready for final digestion with alkalior alkaline salts to reduce to cellulose.

6. The process of treating resinous wood to make cellulose, which consists in subjecting the wood in a closed tank to the action of hot water, thereby forming fatty acids and other solvents, causing the water and acids to circulate in contact with the wood and release the turpentine, oil and rosin, and at the same time distilling off the turpentine andoil vapors and'passing-the rosin off with the water and separating and collecting the same, then drawing ofi the treating liquor, and admitting water and alkaline chemical and digesting the chips till reduced to cellulose.

7. The process of treating and distilling resinous wood to obtain products therefrom, which consists in circulating in contact with the wood in a closed tank hot" water and fatty acid solvents, therebyreleasing from the Wood turpentine, oils and rosin, distilling off and condensing the turpentine and oil vapors, and drawing 'olf and collecting the melted and semi-liquid rosin, blowing out the treating liquor and adding fresh water and alkaline chemical and circulating the same through the cleaned material till reduced to cellulose.

I 8. The process of treating and distilling '125 .temperature .which will develop or form fatty acids, circulating the water and fatty acids diffused therein from the treating tank through a heater and thence in contact with the wood for releasin and extracting turpentine, oils and rosin, distilling off and condensing the turpentine and oil vapors,,

and carrying off the rosin with the circulat ing Water and collecting it in a separate tank, blowing off the treating liquor, then adding fresh water and alkaline chemical to the cleaned material and digesting thelsame till reduced to cellulose.

9. In the manufacture of cellulose, substantially in the manner described, the method of separating or disintegrating the fiber and freeing it from dark liquor, which consists in forcing the cellulose by gas under pressure against atargetin a receiving tank and at the same time injecting a stream of gas under pressure into the jet of cellulose and the distintegrated cellulose for carrying off the water vapor while the freed cellulose is allowed tosettle.

10. The herein described method of disintegrating cellulose and freeing it from black liquor, which consists in forcing the cellulose under pressure against a target and at the same time forcing gas under "pressure into the distintegrated material and carrying off the watery portion with the gas and condensing the same and conducting away the separated gas, while the freed cellulose is allowed to settle.

11. The process of treating wood and plant material to make cellulose, which consists in subjecting the material in a closed tank to the action of fatty acid solvents diffused in hot water, circulating the water and solvents through the material for releasing resinous and gummy matter and floating such matter .off with the water and causing its deposit in a separate chamber while the Water and solvent are again circulated in contact with the material. A

12. The process of treating wood and plant material to make cellulose, which consists in circulating water at a sufficiently high temperature through the material to generate or extract fatty acid solvents and thereby release resinous,-oily and gummy matter from,

E. B. CLARK, BURNETT S. Jonas. 

